The present invention relates to a mechanical pencil capable of feeding new lead by utilizing only the natural force applied thereto when the pencil is gripped during writing.
There have been heretofore provided mechanical pencils having various lead feeding mechanisms, each having inherent deficiencies or drawbacks. For example, in one type in which lead is fed by rotating an axial body of the pencil, both hands are required for the operation and the length of the newly fed lead is not held constant when writing. Also in this type, the lead may easily be broken. Accordingly, such a mechanical pencil is unsuitable for use with thin lead and is now seldom used.
In another type of pencil, a push rod extending from the rear axial body of a mechanical pencil is pressed or tapped to thereby feed a new lead. Although advantageous in that the feeding length of the lead is constant and only one hand is required for feeding the lead, it is disadvantageous in that the gripping form of the hand is changed each time lead is fed.
In a so-called side feeding type where a lead is fed by pushing a single feed plate provided at the finger gripping part, since another finger of the same hand must support the opposite position of the knock plate. Unfortunately the finger gripping form of such a pencil feels unnatural and it is very difficult to perform the feeding operation.
In a mechanical pencil type where an axial body per se is deformed at an obtuse angle to feed a new lead, since an unnatural force must be used to feed the lead, it is very difficult to use.
In a so-called tip end feeding type where a front tip of a mechanical pencil is pushed against a paper or the like, a counter part to which the lead or the tip pipe holding it is held in abutment is required. If the counter part is soft, it is difficult to carry out the feeding operation and the counter part may be damaged or undesirably marked.
In order to eliminate the above-noted defects, an object of the present invention is to provide a novel mechanical pencil in which the natural force used in gripping the axial body of the pencil during the normal writing operation can be utilized for feeding new lead.